Fine chemical combustible powder closed metering and conveying device

Abstract

This invention relates to the field of powder conveying technology and discloses a closed metering and conveying device for fine chemical combustible powders, including a closed storage silo and a metering screw conveyor. The discharge port at the conical bottom of the closed storage silo is sealed and connected to the feed end of the metering screw conveyor. An installation shell is fixed inside the conical section of the closed storage silo by a support frame. A vertically arranged drive shaft is rotatably connected to the bottom of the installation shell. A limit ring is fixedly connected to the inner wall of the conical section of the closed storage silo, and a rotating ring rod is rotatably arranged inside the limit ring. A three-dimensional arch-breaking mechanism is formed by the circumferentially rotating dispersing toothed rod linked to the screw shaft and the vertically reciprocating guide slide rod, thereby achieving the effect of breaking up and loosening the conical silo arches. It can simultaneously break up the annular material arches at the conical wall and the dense material columns in the central area, avoiding bridging, material breakage, and blockage. This stabilizes the discharge flow rate and powder filling density, thus providing uniform and stable feeding conditions for screw metering.

Description

Technical Field

[0001] This invention relates to the field of powder conveying technology, specifically to a closed metering and conveying device for fine chemical combustible powders. Background Technology

[0002] In the fine chemical production process, the closed temporary storage and continuous quantitative conveying of combustible ultrafine powders such as dye intermediates, functional resin micro powders, and catalyst powders are key processes. These powders have small particle size, poor stacking properties, and are prone to bridging and blockage in the silo. Furthermore, the powder friction easily accumulates static electricity, posing a risk of dust explosion. Therefore, high requirements are placed on the airtight reliability, material feeding stability, and explosion-proof safety of the conveying device.

[0003] Currently, the industry commonly uses a complete set of equipment consisting of vertical storage silos and screw conveyors, along with a negative pressure feeding system, to achieve closed feeding, temporary storage, and external conveying of powders. Among them, the volumetric screw conveyor relies on a constant screw pitch to form a metering benchmark and adjusts the conveying flow rate by controlling the spindle speed, which is a common form of continuous quantitative powder feeding. To address the issue of powder bridging in the cone section of storage silos, existing technologies typically employ silo wall vibrators, pneumatic anti-bridging hammers, or an independently driven mixing and dispersing mechanism within the silo. These methods break up material bridging through vibration or mixing, ensuring smooth material flow. However, these anti-bridging solutions have significant limitations under combustible powder conditions: silo wall vibration can force compaction of the powder, exacerbating the accumulation of static electricity between particles and increasing the risk of dust explosion. Independently driven mixing mechanisms require additional explosion-proof drive motors, increasing equipment costs and energy consumption. Furthermore, multiple mounting holes and dynamic sealing structures are needed in the silo wall, increasing the probability of combustible powder leakage and hindering airtight explosion protection. More importantly, existing anti-bridging mechanisms are independent of the screw conveyor system, and the intensity of the anti-bridging action cannot be matched with the conveying flow rate. Sudden collapse of the material bridging can cause instantaneous material surges, leading to drastic fluctuations in the filling coefficient at the screw feed end. This directly disrupts the stable operation of the volumetric screw metering system, resulting in a significant decrease in metering accuracy.

[0004] Therefore, a solution is proposed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a closed metering and conveying device for fine chemical combustible powders, which solves the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a closed metering and conveying device for fine chemical combustible powders, comprising a closed storage silo and a metering screw conveyor, wherein the conical bottom discharge port of the closed storage silo is sealed and connected to the feed end of the metering screw conveyor. The conical section of the sealed storage silo has an installation shell fixed inside by a support frame. The bottom of the installation shell is rotatably connected to a vertically arranged drive shaft II. A limit ring is fixedly connected to the inner wall of the conical section of the sealed storage silo. A rotating ring is rotatably arranged inside the limit ring. Several disintegrating toothed rods are connected to the outer wall of the rotating ring via a fixed rod. A connecting rod is fixedly connected to the bottom end of the drive shaft II. The end of the connecting rod is fixedly connected to the rotating ring. The mounting housing is rotatably connected to a drive shaft, which is connected to a second drive shaft via a bevel gear pair. A drive swing arm is fixedly connected to the outer wall of the drive shaft. A transmission link is hinged to the end of the drive swing arm. A fixed plate is hinged to the bottom end of the transmission link. A guide slide rod is fixedly connected to the top of the fixed plate. The guide slide rod is slidably engaged with the top through hole of the mounting housing. The main screw shaft of the metering screw conveyor is driven to rotate by a synchronous transmission mechanism. The main screw shaft of the metering screw conveyor is linked to a piston gas distribution assembly, which intermittently supplies inert protective gas to the discharge end of the metering screw conveyor.

[0007] Through the above technical solution, the entire device relies on the unified output power of the main shaft of the metering screw conveyor. On the one hand, the synchronous transmission mechanism drives the second drive shaft to rotate, and synchronously drives the outer side of the rotating ring to disperse the toothed rod in a circumferential agitation. In conjunction with the fixed plate, the feed port is continuously loosened, eliminating the problem of powder bridging and clumping in the bin, stabilizing the feeding and filling state, and ensuring the foundation of screw volume metering. On the other hand, the main shaft synchronously links the piston gas distribution component, which can intermittently spray inert gas at the screw discharge end to dilute the oxygen content of the discharged dust at a fixed point. No additional drive and electrical control components are required throughout the process.

[0008] Preferably, the synchronous transmission mechanism includes a first synchronous pulley, a synchronous belt, and a second synchronous pulley. The first synchronous pulley is coaxially and fixedly connected to the extended end of the main screw shaft of the metering screw conveyor. The center of the second synchronous pulley is coaxially and fixedly connected to a horizontally arranged drive shaft. The first synchronous pulley and the second synchronous pulley are connected by a synchronous belt. One end of the drive shaft extends into the interior of the sealed storage silo.

[0009] Through the above technical solution, the first synchronous wheel rotates synchronously with the spiral main shaft, and the rotational power is stably transmitted to the first and second synchronous wheels by the synchronous belt, thereby driving the first drive shaft to rotate synchronously and realizing the power transmission of the spiral main shaft to the arch-breaking mechanism in the warehouse.

[0010] Preferably, a drive block is fixedly connected to the eccentric part of the outer surface of the first synchronous pulley, a movable frame is sleeved on the outer side of the first synchronous pulley, a transverse movable groove is opened on the inner side of the movable frame, the drive block is embedded in the movable groove and forms a sliding fit, a drive rod is fixedly connected to the side of the movable frame, and the drive rod is connected to the power input end of the piston valve assembly.

[0011] With the above technical solution, the eccentrically arranged drive block rotates in a circle with the synchronous wheel, and in conjunction with the movable slot, it transforms into a lateral reciprocating linear motion of the movable frame. Then, it outputs reciprocating power through the drive rod. The mechanical driving force for the nitrogen pumping mechanism can be provided solely by the rotation of the spiral spindle, without the need for electrically controlled drive components.

[0012] Preferably, the piston gas distribution assembly includes a nitrogen storage cylinder, a mounting cylinder, a movable rod, and a driving piston. The mounting cylinder is fixedly connected to the frame outside the sealed storage silo. The driving piston is slidably disposed in the inner cavity of the mounting cylinder. One end of the movable rod is coaxially and fixedly connected to the driving piston, and the other end of the movable rod extends out of the mounting cylinder and is fixedly connected to the driving rod. The outer surface of the mounting cylinder is respectively connected to a connecting pipe one and a connecting pipe two.

[0013] Through the above technical solution, the movable rod follows the drive rod to push and pull the piston back and forth, changing the internal volume of the mounting cylinder to form a periodic pressure difference. This, together with the two pipelines, completes the intake and push of nitrogen gas, and relies on the pure piston mechanical structure to complete the intermittent pumping of inert gas.

[0014] Preferably, the air inlet of the first connecting pipe is connected to the top air port of the nitrogen storage cylinder, the air outlet of the second connecting pipe extends to the inner wall of the cylinder at the discharge end of the metering screw conveyor, and the end of the second connecting pipe is equipped with a directional air nozzle. The directional air nozzle is arranged obliquely along the powder conveying direction, and a one-way tongue flap is installed at the nozzle to prevent powder backflow.

[0015] Through the above technical solution, nitrogen in the gas storage cylinder is transported to the spiral discharge area through pipeline. The unidirectional inclined jet nozzle can avoid backflow of airflow interfering with the upstream metering powder. The one-way tongue can block the pipe opening when the gas is stopped, preventing the ultrafine powder in the cylinder from flowing back into the pipeline and causing gas blockage, thus ensuring long-term stable gas supply.

[0016] Preferably, a worm gear is coaxially fixedly connected to one end of the drive shaft that extends into the sealed storage silo, and a worm wheel is coaxially fixedly connected to the outer wall of the drive shaft. The worm gear and the worm wheel mesh with each other. The bevel gear pair includes a bevel gear one and a bevel gear two. The bevel gear one is coaxially fixedly connected to the top end of the drive shaft two, and the bevel gear two is coaxially fixedly connected to the outer wall of the drive shaft. The bevel gear one and the bevel gear two mesh perpendicularly.

[0017] Through the above technical solution, the worm gear and worm wheel work together to achieve power reduction and torque increase, improve the anti-caking ability of the arch breaking mechanism, and the vertically meshing bevel gear pair converts vertical rotation into horizontal rotation. One set of power input can simultaneously drive two sets of arch breaking actions: circumferential disintegration and vertical reciprocating.

[0018] Preferably, the limiting ring and the rotating ring are both arranged in two sets, upper and lower, along the vertical axis of the conical segment. The two sets of rotating rings are connected by a fixing rod, and multiple dispersing toothed rods are fixedly connected to the fixing rod.

[0019] Through the above technical solution, the double-layer rotating ring combined with multiple dispersing toothed rods can cover the upper and lower areas of the cone section of the storage silo, expand the powder agitation range, break up the material arches formed by different heights of the silo wall in layers, reduce local powder retention and agglomeration, and make the powder fall more evenly in the silo.

[0020] Preferably, both the first connecting pipe and the second connecting pipe are equipped with one-way valves, and the gas conduction directions of the two one-way valves are opposite.

[0021] Through the above technical solution, the two reverse one-way valves form independent gas paths for one-way intake and one-way exhaust. When the piston is driven to move backward, nitrogen is only drawn in from the gas storage tank, and when the piston moves forward, nitrogen is only delivered to the spiral cylinder, thus avoiding gas backflow.

[0022] Preferably, it also includes a vacuum negative pressure unit, wherein the suction end of the vacuum negative pressure unit is connected to the top air chamber of the sealed storage silo through a negative pressure suction pipe, and the upper side wall of the sealed storage silo is connected to a powder suction pipe.

[0023] Through the above technical solution, the negative pressure unit extracts air from the chamber to form a negative pressure environment, and relies on the pressure difference to suck external combustible powder into the chamber through the powder suction pipe in a sealed manner, so as to achieve dust-free and sealed feeding.

[0024] Preferably, the metering screw conveyor has several arc-shaped buffer guide vanes integrally fixedly connected along the axial direction of the screw core. The radial height of the arc-shaped buffer guide vanes is smaller than the outer diameter of the screw blades. The metering screw conveyor has a volume metering section with a constant pitch in the middle of the cylinder.

[0025] Through the above technical solution, a stable volumetric metering benchmark is formed in the constant pitch section, and the synchronously rotating arc-shaped guide vanes continuously agitate the powder, alleviate the axial compression phenomenon of the powder, stabilize the powder bulk density, reduce the conveying error in the volumetric metering process, and improve the quantitative conveying accuracy of the powder.

[0026] This invention provides a closed metering and conveying device for fine chemical combustible powders. It has the following beneficial effects: 1. This invention utilizes a three-dimensional arch-breaking mechanism formed by a circumferentially rotating dispersing toothed rod linked to a spiral spindle and a vertically reciprocating guide slide rod. This mechanism can achieve the effect of breaking up and loosening the cone chamber arches, and can simultaneously break up the annular material arches at the cone wall and the dense material columns in the central area, avoiding bridging, material breakage, and blockage. It can stabilize the feed flow rate and powder filling density, thus providing uniform and stable feeding conditions for spiral metering.

[0027] 2. This invention achieves a pulsed nitrogen inertization protection effect that adaptively matches the screw conveyor speed by using a piston-type intermittent gas distribution component with eccentric linkage of the screw main shaft and a directional jet nozzle tilted in the same direction at the discharge end. This can dilute the oxygen concentration and eliminate static electricity in the powder in high-risk areas of the discharge dust cloud, while avoiding continuous gas supply disturbance to the powder layer in the upstream metering section, thus significantly reducing the consumption of inert gas. Attached Figure Description

[0028] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the negative pressure extraction pipe structure of the present invention; Figure 3 This is a schematic diagram of the limiting ring structure of the present invention; Figure 4 This is a schematic diagram of the disintegrating toothed rod structure of the present invention; Figure 5 This is a schematic diagram of the drive shaft structure of the present invention; Figure 6 This is a cross-sectional view of the interior of the mounting housing of the present invention; Figure 7 This is a schematic diagram of the fixing plate structure of the present invention; Figure 8 for Figure 2 Enlarged view of point A in the middle; Figure 9 This is a schematic diagram of the internal structure of the mounting cylinder of the present invention.

[0029] Among them, 1. Metering screw conveyor; 2. Enclosed storage silo; 32. Limiting ring; 33. Rotating ring; 34. Fixing rod; 35. Dispersing gear; 36. Connecting rod; 37. Fixing plate; 38. Drive shaft; 39. Guide slide rod; 30. Transmission connecting rod; 310. Drive swing arm; 42. Nitrogen storage cylinder; 43. Connecting pipe one; 44. Connecting pipe two; 45. Mounting cylinder; 46. Movable rod; 47. Drive piston; 52. Synchronous pulley 1; 53. Drive block; 54. Movable frame; 55. Drive rod; 56. Synchronous belt; 57. Synchronous pulley 2; 58. Drive shaft 1; 59. Drive shaft 2; 50. Worm gear; 510. Worm; 511. Bevel gear 1; 512. Bevel gear 2; 61. Mounting housing; 62. Support frame; 7. Vacuum negative pressure unit; 8. Negative pressure extraction pipe; 9. Powder suction pipe. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1: Please see the appendix Figure 1 Appendix Figure 3 and attached Figure 4 This invention provides a closed metering and conveying device for fine chemical combustible powders, including a vertically arranged closed storage silo 2 and a horizontally arranged metering screw conveyor 1. The cone-shaped discharge port of the closed storage silo 2 is sealed to the feed end of the metering screw conveyor 1 via a flange. A sealed gate valve is provided at the connection position. This valve can cut off the discharge passage during equipment maintenance or operation mode switching, preventing the powder in the closed storage silo 2 from continuously flowing into the metering screw conveyor 1 under gravity. It also facilitates maintaining the silo's sealed state when the screw conveyor is maintained separately. A vacuum negative pressure unit 7 is provided as a supporting device. The suction end of the vacuum negative pressure unit 7 is connected to the top air chamber of the sealed storage silo 2 through a negative pressure extraction pipe 8. A powder suction pipe 9 is connected to the upper side wall of the sealed storage silo 2. A dust removal filter element is installed in the top air chamber of the sealed storage silo 2, which can intercept ultrafine powder particles during the suction process and prevent powder from entering the negative pressure extraction pipe 8 with the airflow, causing wear on the impeller of the vacuum negative pressure unit 7. A central support and transmission assembly are provided inside the conical section of the sealed storage silo 2. The central mounting shell 61 is fixed to the inner wall of the conical section by multiple sets of support frames 62. The support frames 62 are along the... The silo walls are evenly arranged circumferentially, ensuring both the coaxiality and structural rigidity of the mounting shell 61, while also providing ample channels for powder to fall without obstructing normal powder descent. A vertically arranged drive shaft 58 is rotatably connected to the bottom of the mounting shell 61, with its lower end extending above the discharge port. Two sets of limiting rings 31 are coaxially fixed to the inner wall of the conical section of the sealed storage silo 2. Each set of limiting rings 31 has a rotating ring 32 rotatably mounted on its inner side. The two sets of rotating rings 32 are rigidly connected by multiple vertical fixing rods 33, forming an integrated rotating frame. Each fixing rod 33... Multiple dispersing toothed rods 34 are fixed axially at intervals on the outer wall of the 3. The upper and lower layers of dispersing toothed rods 34 are staggered circumferentially. The dispersing toothed rods 34 extend radially outward to a position close to the inner wall of the cone section, which can continuously shear the powder near the bin wall, breaking up the annular material arch and adhering agglomerates at the bin wall. A connecting rod 35 is radially fixed at the bottom end of the drive shaft 2 58. The outer end of the connecting rod 35 is fixedly connected to the inner side of the lower rotating ring 32, so that the rotational torque of the drive shaft 2 58 can be transmitted to the entire rotating frame through the connecting rod 35, driving all the dispersing toothed rods 34 to perform circumferential rotational motion.

[0032] Example 2: Please see the appendix Figure 2 Appendix Figure 5 Appendix Figure 6 and attached Figure 7 Inside the mounting housing 61, a horizontally arranged drive shaft 37 is rotatably connected via a bearing assembly. The drive shaft 37 and the second drive shaft 58 form a reversing transmission through a bevel gear pair. The bevel gear pair includes a first bevel gear 511 coaxially fixed to the top of the second drive shaft 58 and a second bevel gear 512 coaxially fixed to the outer wall of the drive shaft 37. The two are in a vertical meshing state, which can change the vertical rotation of the second drive shaft 58 into the horizontal rotation of the drive shaft 37. A drive swing arm 310 is fixed to the outer wall of the drive shaft 37. A transmission link 39 is hinged to the outer end of the drive swing arm 310. A horizontally arranged fixed plate 36 is hinged to the bottom end of the transmission link 39. Two guide slide rods 38 are symmetrically fixed to the top of the fixed plate 36. The guide slide rods 38 pass upward through the guide through hole at the top of the mounting shell 61 and form a sliding fit, which forms a linear limit on the vertical movement of the fixed plate 36 to avoid swaying and jamming during the movement. The outer wall of the guide slide rod 38 is provided with multiple sets of radially protruding dispersing tooth structures along the axial direction. When the guide slide rod 38 moves vertically reciprocating synchronously, it can form a vertical penetrating disturbance on the powder in the central area of ​​the cone chamber, directly piercing the dense material column in the central part. It forms a three-dimensional dispersing effect with the circumferentially rotating dispersing tooth rod 34. At the same time, the lower surface of the fixed plate 36 is provided with downwardly protruding unblocking teeth, which can directly act on the dense powder at the discharge port to prevent the discharge port from being blocked and ensure continuous and smooth discharge.

[0033] This embodiment is an implementation method for strengthening the arch-breaking structure. Designed for combustible powders that are prone to agglomeration, have poor flowability, and a strong tendency to bridge, it strengthens the arch-breaking and unblocking mechanism within the storage chamber based on the basic structure of Embodiment 1. Multiple layers of rotating rings 32 are vertically arranged along the conical section. The dispersing teeth 34 corresponding to each layer of rotating rings 32 are arranged in an inclined, staggered manner, with the ends of the teeth inclined towards the direction of powder descent, enhancing the shearing and breaking effect on agglomerated powder. The dispersing teeth on the outer wall of the guide slide rod 38 employ multiple... The pyramidal structure can further pierce the dense material column when vertically penetrating, and the dispersing teeth of the adjacent guide slide rods 38 are distributed vertically in a staggered manner. Multiple downward-extending unblocking cone teeth are added to the lower surface of the fixed plate 36. The unblocking cone teeth are directly facing the discharge port channel and can directly extend into the discharge port when the fixed plate 36 reciprocates, avoiding blockage at the narrow diameter of the discharge port. The lower part of the connecting rod 35 is equipped with auxiliary material-pulling teeth, which further loosen the powder above the discharge port when rotating synchronously with the rotating ring 32.

[0034] Example 3: Please see the appendix Figure 5 Appendix Figure 8 and attached Figure 9The extended end of the screw main shaft of the metering screw conveyor 1 is equipped with a synchronous transmission mechanism for outputting power to the arch-breaking mechanism inside the silo. The synchronous transmission mechanism includes a first synchronous pulley 51, a synchronous belt 55, and a second synchronous pulley 56. The first synchronous pulley 51 is coaxially fixed to the extended end of the screw main shaft, and the second synchronous pulley 56 is coaxially fixed to the outer end of the horizontally arranged drive shaft 57. The first synchronous pulley 51 and the second synchronous pulley 56 are driven by the meshing of the synchronous belt 55. The inner end of the drive shaft 57 extends through the side wall of the sealed storage silo 2 into the silo, and a worm gear 5 is coaxially fixed to the end of the drive shaft 57 that extends into the silo. 10. A worm gear 59 is coaxially fixed to the outer wall of the second drive shaft 58. The main screw shaft of the metering screw conveyor 1 is also linked to a piston gas distribution assembly for intermittently conveying inert protective gas to the discharge end. A drive block 52 is eccentrically fixed to the outer end face of the first synchronous wheel 51. A movable frame 53 is sleeved on the outer side of the first synchronous wheel 51. A transverse movable groove is opened on the inner side of the movable frame 53. The drive block 52 is embedded in the movable groove and forms a sliding fit. When the screw shaft rotates, the eccentrically set drive block 52 can drive the movable frame 53 to reciprocate in a linear motion along the transverse direction, converting the rotational motion into linear reciprocating motion. A drive rod 54 is fixed to the side of the movable frame 53. The end of the drive rod 54 is connected to the power input end of the piston gas distribution assembly. The piston gas distribution assembly includes a nitrogen storage cylinder 41, a mounting cylinder 44, a movable rod 45, and a drive piston 46. The mounting cylinder 44 is fixed on the frame outside the sealed storage silo 2. The drive piston 46 is slidably disposed in the inner cavity of the mounting cylinder 44. One end of the movable rod 45 is coaxially fixed with the drive piston 46, and the other end passes through the end cap of the mounting cylinder 44 and is fixedly connected to the drive rod 54. The end of the mounting cylinder 44 is connected to a connecting pipe 42 and a connecting pipe 43. Both pipes are equipped with one-way valves and have opposite directions of conduction, forming a one-way pumping air path. The air inlet of the connecting pipe 42 is connected to the top air port of the nitrogen storage cylinder 41. The air outlet of the connecting pipe 43 extends to the inner wall of the cylinder at the discharge end of the metering screw conveyor 1. The end is equipped with a directional air nozzle. The directional air nozzle is arranged at an angle along the powder conveying direction. The sprayed nitrogen airflow can carry the powder in the same direction, avoiding reverse disturbance of the powder layer in the upstream metering section and ensuring stable metering conditions.

[0035] The metering screw conveyor 1 has a constant pitch volumetric metering section in the middle of its cylinder. The outer diameter of the screw blades in this section is uniform, and the gap between the screw blades and the inner wall of the cylinder is uniform, forming a stable single-rotation conveying volume reference. The theoretical conveying flow rate can be adjusted by controlling the main shaft speed. Several arc-shaped buffer guide blades are integrally fixed along the axial direction on the outer wall of the screw core corresponding to the volumetric metering section. The radial height of the arc-shaped buffer guide blades is smaller than the outer diameter of the screw blades. Adjacent arc-shaped buffer guide blades are staggered along the axial direction. When the arc-shaped buffer guide blades rotate synchronously with the screw main shaft, they can apply continuous radial disturbance to the powder layer, break the axially continuous dense powder column, and avoid the powder from being continuously squeezed, which would lead to an increase in bulk density.

[0036] This embodiment is an enhanced explosion-proof configuration implementation. Based on the basic structure of Embodiment 1, it features optimized design. Two sets of piston gas distribution assemblies are symmetrically arranged along the cylinder, synchronously driven by an eccentric drive structure on the synchronous pulley 51. Multiple directional jet nozzles are arranged circumferentially along the inner wall of the cylinder at the discharge end of the metering screw conveyor 1. These nozzles collectively form a surrounding inert gas curtain, covering the suspended dust cloud area at the discharge port. The arc-shaped buffer guide vanes within the volumetric metering section employ a rounded chamfered edge structure, and the vane surface is treated with anti-static agents to reduce static electricity generated by powder friction. This embodiment achieves a pulsed nitrogen inertization protection effect that adaptively matches the screw conveyor speed. It can precisely dilute the oxygen concentration and eliminate static electricity in the high-risk area of ​​the discharge dust cloud, while avoiding continuous gas supply disturbance to the powder layer in the upstream metering section, significantly reducing inert gas consumption.

[0037] Working principle: During the initial feeding stage, the vacuum negative pressure unit 7 first extracts air from the top air chamber of the sealed storage silo 2 through the negative pressure extraction pipe 8, creating a stable negative pressure environment inside the silo. Under the pressure difference, external combustible powder is drawn into the sealed storage silo 2 through the powder suction pipe 9. The powder falls along the silo wall and accumulates in the conical section area. The dust removal filter element built into the top of the silo can prevent ultrafine powder from entering the negative pressure pipeline with the airflow, avoiding powder overflow and wear on the vacuum unit. After the metering screw conveyor 1 starts, the screw shaft will drive the synchronous wheel 51 connected to it to rotate. Power is transmitted to synchronous pulley 56 via synchronous belt 55, which in turn drives drive shaft 57 to rotate synchronously. The end of drive shaft 57 extending into the chamber drives worm gear 510 to rotate. Worm gear 510 drives drive worm wheel 59 and drive shaft 58 to rotate around the vertical axis. During the rotation of drive shaft 58, the output is divided into two paths: one path pulls rotating ring 32 to rotate circumferentially along the inner side of limiting ring 31 through connecting rod 35 at the bottom. Fixed rod 33 rotates synchronously with rotating ring 32, driving multiple dispersing toothed rods 34 to continuously circumferentially agitate the powder inside the cone section, breaking up the powder formed at the cone wall. To prevent material arching and agglomeration, and to avoid material interruption caused by powder bridging, another path is taken through the vertical meshing of bevel gear 511 and bevel gear 512 at the top of drive shaft 2 58, which converts the vertical rotation into horizontal rotation, driving drive shaft 37 to rotate inside mounting housing 61. At this time, drive swing arm 310 fixed to the outer wall of drive shaft 37 swings in a circular motion, and the rotational motion is converted into vertical reciprocating linear motion through transmission link 39, which pulls fixed plate 36 to move up and down vertically. Guide slide rod 38 rises and falls synchronously with fixed plate 36, wherein guide slide rod 38 Multiple sets of dispersing tooth structures are arranged axially on the outer wall of rod 8. With the up-and-down reciprocating movement of guide slide rod 38, they vertically penetrate and disturb the powder inside the central area of ​​the cone chamber, directly piercing the dense material column and arch structure formed in the central part. Together with the dispersing tooth rod 34 rotating circumferentially near the cone wall, they form a three-dimensional arch-breaking and dispersing effect, which avoids powder bridging and local agglomeration in all aspects. At the same time, they continuously loosen the powder directly above the discharge port, so that the powder can fall stably into the feed end of the metering screw conveyor 1 below, providing uniform and stable feeding and filling conditions for subsequent volume metering. After the powder enters the metering screw conveyor 1, it is conveyed forward along the axial direction of the cylinder as the screw blades rotate. The volumetric metering section in the middle of the cylinder adopts a constant pitch design, and the gap between the screw blades and the inner wall of the cylinder is uniform. Combined with the stable filling coefficient formed by the upstream steady flow feed, the volume of powder conveyed by the screw in one revolution remains constant, thus realizing continuous volumetric metering. During the conveying process, the arc-shaped buffer guide vanes on the screw spindle rotate synchronously with the main shaft, continuously applying radial disturbance to the powder layer, breaking the axially continuous dense powder column, and avoiding the powder from being continuously squeezed and increasing the bulk density. While the screw main shaft drives the synchronous wheel 51 to rotate, the eccentric drive block 52 fixed to the end face of the synchronous wheel 51 moves in a circular motion. The drive block 52 is embedded in the transverse movable groove inside the movable frame 53. Through eccentric rotation, it drives the movable frame 53 to move in a transverse reciprocating linear motion. The drive rod 54 on the side of the movable frame 53 synchronously pulls the movable rod 45 back and forth. The movement of the piston 46 causes it to slide back and forth in the inner cavity of the mounting cylinder 44. When the piston 46 moves outward, a negative pressure is formed in the inner cavity of the mounting cylinder 44, and the one-way valve in the connecting pipe 1 42 is opened. The inert nitrogen in the nitrogen storage cylinder 41 is drawn into the inner cavity of the mounting cylinder 44 through the connecting pipe 1 42. When the piston 46 pushes inward, the pressure in the inner cavity increases, the one-way valve in the connecting pipe 1 42 closes, and the one-way valve in the connecting pipe 2 43 is opened. The pressurized nitrogen is pushed through the connecting pipe 2 43 to the directional jet nozzle at the discharge end of the metering screw conveyor 1. It is sprayed into the discharge area in a pulse form. The directional jet nozzle is arranged at an angle along the powder conveying direction. The nitrogen airflow carries the powder together and flows towards the discharge port. It will not disturb the powder layer in the upstream metering section in the reverse direction. It can also form an inert gas atmosphere locally at the discharge port, dilute the oxygen concentration of the suspended dust cloud at the moment of discharge, and further break up the compacted powder clumps and eliminate static electricity on the powder surface.

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A closed metering and conveying device for fine chemical combustible powder, comprising a closed storage silo (2) and a metering screw conveyor (1), wherein the discharge port of the closed storage silo (2) is closedly connected to the feed end of the metering screw conveyor (1), characterized in that: The conical section of the sealed storage silo (2) is fixedly connected to a mounting shell (61) by a support frame (62). A vertically arranged drive shaft (58) is rotatably mounted on the mounting shell (61). The lower end of the drive shaft (58) is linked to a circumferential rotating frame. When the drive shaft (58) rotates, it can drive the circumferential rotating frame to rotate along the circumference of the conical section, loosening the powder at the conical wall. The drive shaft (58) is linked to a vertical reciprocating insertion mechanism through a reversing transmission mechanism. The vertical reciprocating insertion mechanism can move back and forth vertically, loosening the powder in the central area of ​​the conical section. The main screw of the metering screw conveyor (1) is driven by the synchronous transmission mechanism to drive the second drive shaft (58) to rotate. The main screw is driven by the eccentric mechanical structure rigid linkage piston gas distribution assembly to reciprocate when the main shaft rotates, so that the piston gas distribution assembly intermittently delivers inert protective gas to the discharge end of the metering screw conveyor (1).

2. The closed metering and conveying device for fine chemical combustible powder according to claim 1, characterized in that: The circumferential rotating frame includes a limiting ring (31), a rotating ring (32), a fixing rod (33), and a disintegrating gear (34). The limiting ring (31) is coaxially fixed to the inner wall of the conical section along the axial direction. The rotating ring (32) is rotatably sleeved on the inner ring surface of the limiting ring (31). The outer wall of the rotating ring (32) is connected to several disintegrating gears (34) via the fixing rod (33). The bottom end of the second drive shaft (58) is fixedly connected to the rotating ring (32) via a connecting rod (35). The reversing transmission mechanism is a bevel gear pair. The vertical reciprocating insertion mechanism includes a drive shaft (37), a drive shaft (38), and a drive shaft (39). The components include a swing arm (310), a transmission link (39), a fixed plate (36), and a guide slide rod (38). The drive shaft (37) is rotatably connected inside the mounting housing (61). The drive shaft (37) is connected to the drive shaft (58) via a bevel gear pair. The drive swing arm (310) is fixedly connected to the outer wall of the drive shaft (37). The end of the drive swing arm (310) is hinged to the fixed plate (36) via the transmission link (39). The guide slide rod (38) is fixedly connected to the top of the fixed plate (36), and the guide slide rod (38) slides with the top through hole of the mounting housing (61).

3. The closed metering and conveying device for fine chemical combustible powder according to claim 2, characterized in that: The synchronous transmission mechanism includes a first synchronous pulley (51), a synchronous belt (55), a second drive shaft (58), and a second synchronous pulley (56). The first synchronous pulley (51) is coaxially and fixedly connected to the extended end of the main screw shaft of the metering screw conveyor (1). The center of the second synchronous pulley (56) is coaxially and fixedly connected to a horizontally arranged first drive shaft (57). The first synchronous pulley (51) and the second synchronous pulley (56) are connected by a synchronous belt (55). One end of the first drive shaft (57) passes into the interior of the sealed storage silo (2). The second drive shaft (58) is rotatably connected to the bottom of the mounting housing (61). A drive block (52) is fixedly connected to the eccentric part of the outer surface of the first synchronous wheel (51). A movable frame (53) is sleeved on the outer side of the first synchronous wheel (51). A transverse movable groove is opened on the inner side of the movable frame (53). The drive block (52) is embedded in the movable groove and forms a sliding fit. A drive rod (54) is fixedly connected to the side of the movable frame (53). The drive rod (54) is connected to the power input end of the piston valve assembly.

4. The closed metering and conveying device for fine chemical combustible powder according to claim 3, characterized in that: The piston gas distribution assembly includes a nitrogen storage cylinder (41), an installation cylinder (44), a movable rod (45), and a drive piston (46). The installation cylinder (44) is fixedly connected to the frame outside the sealed storage silo (2). The drive piston (46) is sealed and slidably disposed in the inner cavity of the installation cylinder (44). One end of the movable rod (45) is coaxially fixedly connected to the drive piston (46). The other end of the movable rod (45) passes through the installation cylinder (44) and is fixedly connected to the drive rod (54). The outer surface of the installation cylinder (44) is connected to a connecting pipe one (42) and a connecting pipe two (43). The air inlet end of the connecting pipe one (42) is connected to the top air port of the nitrogen storage cylinder (41). The air outlet end of the connecting pipe two (43) extends to the inner wall of the cylinder at the discharge end of the metering screw conveyor (1).

5. A closed metering and conveying device for fine chemical combustible powders according to claim 4, characterized in that: The end of the connecting pipe 2 (43) is equipped with a directional jet nozzle, which is arranged at an angle along the powder conveying direction, and a one-way tongue flap is installed at the nozzle to prevent powder backflow.

6. A closed metering and conveying device for fine chemical combustible powders according to claim 5, characterized in that: The drive shaft one (57) is coaxially fixedly connected to a worm gear (510) at one end that extends into the sealed storage silo (2). The outer wall of the drive shaft two (58) is coaxially fixedly connected to a worm wheel (59). The worm gear (510) and the worm wheel (59) mesh with each other. The bevel gear pair includes a bevel gear one (511) and a bevel gear two (512). The bevel gear one (511) is coaxially fixedly connected to the top end of the drive shaft two (58). The bevel gear two (512) is coaxially fixedly connected to the outer wall of the drive shaft (37). The bevel gear one (511) and the bevel gear two (512) mesh perpendicularly.

7. A closed metering and conveying device for fine chemical combustible powders according to claim 2, characterized in that: The limiting ring (31) and the rotating ring (32) are both arranged in two sets, one above the other, along the vertical axis of the cone section. The two sets of rotating rings (32) are connected by a fixing rod (33), and multiple disintegrating toothed rods (34) are fixedly connected to the fixing rod (33).

8. A closed metering and conveying device for fine chemical combustible powders according to claim 4, characterized in that: Both the first connecting pipe (42) and the second connecting pipe (43) are equipped with one-way valves, and the gas conduction directions of the two one-way valves are opposite.

9. A closed metering and conveying device for fine chemical combustible powders according to claim 1, characterized in that: It also includes a vacuum negative pressure unit (7), the suction end of which is connected to the top air chamber of the sealed storage silo (2) through a negative pressure suction pipe (8), and the upper side wall of the sealed storage silo (2) is connected to a powder suction pipe (9).

10. A closed metering and conveying device for fine chemical combustible powders according to claim 1, characterized in that: The metering screw conveyor (1) has several arc-shaped buffer guide vanes integrally fixedly connected along the axial direction of the screw core shaft inside. The radial height of the arc-shaped buffer guide vanes is less than the outer diameter of the screw blades. The metering screw conveyor (1) has a volume metering section with a constant pitch in the middle of the cylinder.

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